A universal joint, commonly referred to as a universal coupling, a U-joint, Cardan joint, Hardy-Spicer joint or Hooke's joint is a joint or coupling to a rigid rod that allows the rod to “bend” in any direction and is commonly used for shafts that transmit rotary motion. The joint consists of a pair of hinges or yokes located close together and oriented at 90 degrees to each other, connected by a cross shaft. Universal joints have been used for many hundreds of years and are presently used in many applications, including industrial and automotive. The method of this invention may be used to form a Cardan or double Cardan joint as used, for example, in automotive applications.
At present, the hinge components or yokes of a universal joint are cast and machined. This is an expensive, time consuming process. More importantly, the cast hinge members or yokes typically are not balanced. As will be understood by those skilled in the art, an automotive universal joint must rotate rapidly and if the hinge members or yokes are out of balance, the universal joint will vibrate, sometimes violently or even destructively. Thus, the automotive industry has developed various vibration damping devices to damp the vibration of the universal joint as disclosed, for example, in U.S. Pat. No. 6,520,678. As will be understood, vibration dampers are expensive and also subject to failure.
There is, therefore, a long felt need for a method of making a constant velocity universal joint which is relatively inexpensive, avoids expensive casting and machining operations, reduces weight and results in a balanced universal joint assembly, eliminating the requirement for vibration damping.